Abstract: Aiming to the purpose of study on in-situ steel analysis for componental elements, an experimental platform of laser induced breakdown spectroscopy (LIBS) was established by using laser and spectrometer. A multi-dimensional non-coaxial optical path was designed and softwares for equipment driving, for searching for spectral peaks of the elements, and for quantitative analysis of steel for its componental elements were developed. The 21 samples with different contents of C, Mn, Si, Cr, Ni, Cu were chosen for testing by LIBS. Through optimization of choice of analytical spectral lines and spectral lines of internal standard, satisfactory correlationships were obtained with correlation coefficients of the 6 elements all over 0.910. From the 21 samples, 12 samples with closer contents of Cu, Si and Mn were chosen for a further study on the correlationships, and it was found that the correlation coefficients of the 3 elements were raised significantly, for example values for Mn and Si were raised to 0.975 and 0.963 respectively. But in the determination of S and P under the same condition, correlation coefficients of 0.256, 0.682 respectively were found. This problem was remained to be studied further. In addition, the rule of effect of temperature of sample on the intensity of spectral line of the element was tested preliminarily.